body,p,ul,ol,li,dl,dt,dd,h1,h2,h3,h4,h5,h6,form,fieldset,legend,input,select,textarea,button,th,td,menu{margin:0;padding:0;}
ul,dl,ol{list-style:none;}
img,fieldset,input[type="submit"]{border:0 none;}
em{font-style:normal;}
strong{font-weight:normal;}
table{border-collapse:collapse;border-spacing:0;}
button,input[type="button"]{cursor:pointer;border:0 none;}
a,button,input,img{-webkit-touch-callout:none;}
img{/*pointer-events:none;*//*禁止图片的点击事件，例如长按保存图片*/}
input,select,textarea{outline:none;}
a{text-decoration:none;}
.fl{ float: left}
.fr{ float: right}
.clear{clear:both;width:0 !important;height:0 !important;float:none !important;content:"";display:block;} 
.none{display: none;}
html,body{
/*禁止用户选择元素*/
/*-moz-user-select:none;
-webkit-user-select: none;
-ms-user-select: none;
 -khtml-user-select:none; */
 -webkit-tap-highlight-color:rgba(0, 0, 0, 0);
 /*禁止元素点击出现半透明黑色背景*/ }
html {height: 100%;width: 100%;outline: 0;-webkit-text-size-adjust:none;}
body {height: 100%;margin: 0;position: relative;font-family: helvetica;font-size: 28px;color: #333;}
input,textarea{font-size: 28px;font-family: helvetica !important;-webkit-appearance: none;appearance: none;border: none;border-radius: 0;}
.wrapper{width: 750px;margin: 0 auto;}
.header{background: #454545;color: #fff;text-align: center;position: relative;height: 90px;line-height: 90px;font-size: 36px;position: fixed;left: 50%;width: 750px;z-index: 20;-webkit-transform: translateX(-50%);transform: translateX(-50%);}
.header a{display: block;position: absolute;color: #fff;top: 50%;-webkit-transform: translateY(-50%);transform: translateY(-50%);}
.header .return-btn{left: 4%;}
.header .return-btn::before{content: "";display: inline-block;width: 28px;height: 28px;border: solid #fff;border-width: 3px 0 0 3px;transform: rotate(-45deg);-webkit-transform: rotate(-45deg);}
.header .menu-btn{right: 2%;font-size: 50px;font-weight: 600;}
